Two humans oncogenes been cloned from NIH3T3 cells transformed with transfected human DNAs. One gene, c-fgf3, was activated during transfection by fusion of the gene with a retrovirus promoter/enhancer. The encoded protein (FGF-3) is related to acidic and basic fibroblast growth factors as well as to the oncoproteins int2 and hst. The other cloned oncogene is activated in the osteosarcoma cell line SAOS2. This proposal describes experiments to investigate the normal functions of these genes as well as their roles in neoplasia. The structure of the normal c-fgf3 gene will be fully characterized. FGF-3 protein will purified from mammalian cells and from bacteria expressing a trpE-FGF-3 fusion product. The mitogenic spectrum of FGF-3 will be compared with that of classic FGFs. Biosynthesis of FGF-3 in mammalian cells will be studied with the aid of antibodies raised against FGF-3 protein and synthetic peptides. The FGF-3 receptor will be characterized by competition binding experiments and by crosslinking radiolabelled FGF-3 to its receptor. The expression of c-fgf3 in normal and neoplastic cells will be examined by Northern and Western blotting, and expressing within tissues will be localized by in situ hybridization. The role of FGF-3 in tumor development will be studied by comparing the growth in vivo of tumor cells expressing FGF-3 versus the same cells in which FGF-3 production in blocked by anti-sense RNA technology. The identity of the SAOS2 oncogene will be determined by sequencing the corresponding cDNA clone. The mutation(s) which distinguish(es) the SAOS2 activated gene from the normal allele will be determined by characterizing chimeric gene constructs and by DNA sequencing. An appropriate assay will screen for other tumors in which the same activating mutation had occurred.